In a small heavy saucepan melt chocolate pieces over low heat,
stirring constantly. Remove from heat. Stir in walnuts, sour cream,
brandy or brandy extract, and 1/4 teaspoon ground nutmeg. Transfer
mixture to a bowl. Cover and chill at least 2 hours or until
chocolate mixture is firm enough to shape into balls.

Line a baking sheet with waxed paper; set aside.
In a small bowl combine powdered sugar, cinnamon, and 1/4 teaspoon
ground nutmeg; set aside. Shape chilled truffle mixture into
3/4-inch balls. Roll each ball in the powdered sugar mixture and
place on prepared baking sheet. Cover and chill until firm. Store
truffles tightly covered in the refrigerator for up to 2 weeks. Let
stand at room temperature about 30 minutes before serving.